1. Field of the Invention
The present invention relates to the curving of sheets of glass in accordance with the technique wherein the sheets of glass are heated to the curving temperature in a horizontal position in a continuous furnace and are pressed against a curving form with a solid surface by means of a forming frame in a curving station arranged after the continuous furnace, then are taken to a cooling station by means of a support frame.
2. Background of the Prior Art
In the case of the known method described above, the sheets of glass enter the curving station on a bed of hot gas, are pressed against the solid surface curving form by means of a forming frame which can be moved upward and downward, are held by suction against the solid surface curving form and, after lowering the forming frame, are deposited on a support which can be translated between the curving station and the cooling station (U.S. Pat. No. 3,846,104).
This known method does not enable the manufacture of glazings with complex curves, that is, glazings which have both convex curved areas and concave curved areas.
In addition, a method for curving sheets of glass is known, in accordance with which, in the curving station, a current of hot gas is directed onto the sheets of glass and the flow as well as the pressure of the current of hot gas are regulated such that the sheets of glass are pressed by said current of hot gas against the curving form and are curved into their final shape (EP 169,770). Using this known method, it is indeed possible to act on the majority of the surface of the glazing using uniform pressure and, thus, to produce complex shapes. However, since, in this method, the curving forces are essentially produced by the dynamic pressure of the gas current and since the fraction of dynamic pressure which can be used for the curving is generally insufficient in the marginal areas of the sheets of glass, that is, in the regions where they are highly curved towards the top and do not permit pressing of these marginal areas in order to apply them closely against the curving form, this known method of curving is not suitable for the manufacture of very highly curved glazings.
The object of the invention is to develop a method such that even very highly curved glazings and/or those with complex curves can be manufactured.